Comparison between Dicationic and Monocationic Ionic Liquids: Liquid Density, Thermal Properties, Surface Tension, and Shear Viscosity

Abstract

We report the data of liquid density, thermal properties including glass transition temperature, melting point, and decomposition temperature, surface tension, and shear viscosity for imidazolium-based dicationic ionic liquids with the anions of bis(trifluoromethylsulfonyl)amide, bis(pentafluoroethylsulfonyl)amide, tetrafluoroborate, and nitrate. To find the unique and general features of the dicationic ionic liquids, data of their corresponding monocationic ionic liquids are also summarized. The results of the dicationic ionic liquids showed that the density was high; the glass transition temperature and melting point were high, and they were thermally stable. Also the surface tension was large, and the shear viscosity was high in comparison with the reference monocationic ionic liquids. The data of the physical properties including liquid density, surface tension, and shear viscosity of the ionic liquids were also compared with that of alkanediols and alkyl alcohols to find the alkyene-linker and alkyl-group dependences in the ionic liquids and alcohols.

Designing highly efficient solvents for the Knoevenagel condensation: two novel dicationic dimethyl phosphate ionic liquids

“…Although the conversion of 4-(dimethylamino)benzaldehyde (6) in the medium of ILs 3-5 is similar, our attempts to clarify the suitability of dicationic dimethyl phosphate ILs for the Knoevenagel condensation have resulted in the development of two previously unreported compounds. Since DILs usually have enhanced chemical and physical properties 14,15 and decreased toxicity 16 in comparison to monocationic ILs, these new DILs might be a subject of interest in the context of environmentally friendly organic synthesis that benefit from the structural peculiarities of these ILs.…”

“…Ionic liquids (ILs) -structurally divergent compounds with beneficial and finetunable properties 10,11 -have recently been presented as alternative and efficient solvents or catalysts 1,12,13 for environmentally benign Knoevenagel condensations. As a distinct group, dicationic ionic liquids (DILs) frequently possess enhanced chemical and physical properties, 14,15 as well as decreased toxicity 16 in comparison to the respective monocationic ILs. Several DILs have been successfully applied in the Knoevenagel condensation.…”

Time-Resolved Characterization of Dynamic Tribochemical Processes for Dicationic Imidazolium Ionic Liquid

“…The structures of the dicationic IL (IL2-di) and its monocationic analogue (IL2), which was used as a benchmark in this study, are shown in Figure 1. connecting chain [28][29][30][31] that was associated with better tribological properties, higher stability, lower toxicity and corrosiveness of the dicationic ILs [14,[31][32][33][34][35][36][37][38][39][40][41]. In the literature, there is a consensus of opinions that the good friction-reduction and wearresistant properties of ILs are owed to their ability to form stable adsorbed layers and protective tribofilms [4,27,[42][43][44].…”

“…Another approach relies on bridging two cationic head groups by PEG chain. Molecular dynamics simulation and advanced spectroscopy have revealed significant differences in structural heterogeneity and nano-organization between monocationic and geminal dicationic ILs with a long connecting chain [28][29][30][31] that was associated with better tribological properties, higher stability, lower toxicity and corrosiveness of the dicationic ILs [14,[31][32][33][34][35][36][37][38][39][40][41].…”

The Dynamical Properties on Ionic Liquids: Insights from Molecular Dynamics Study

“…In all the simulations, all the stretching bonds were constrained with the SHAKE algorithm [42] [13,43]. 12 Å was set as cutoff length.…”